//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


using System;

namespace EffiProzDB
{

    /**
     * Maintains a sequence of numbers.
     *
     * @author  fredt@users
     * @since 1.7.2
     * @version 1.7.2
     */
    public class NumberSequence
    {

        HsqlNameManager.HsqlName name;

        // original start value - used _in CREATE and ALTER commands
        private long startValue;

        // present value
        private long currValue;

        // last value
        private long lastValue;
        private long increment;
        private int dataType;

        /**
         * constructor with initial value and increment;
         */
        public NumberSequence(HsqlNameManager.HsqlName name, long value, long increment,
                              int type)
        {

            this.name = name;
            startValue = currValue = lastValue = value;
            this.increment = increment;
            dataType = type;
        }

        /**
         * principal getter for the next sequence value
         */
        public long getValue()
        {
            lock (this)
            {
                long value = currValue;

                currValue += increment;

                return value;
            }
        }

        /**
         * getter for a given value
         */
        public long getValue(long value)
        {
            lock (this)
            {
                if (value >= currValue)
                {
                    currValue = value;
                    currValue += increment;

                    return value;
                }
                else
                {
                    return value;
                }
            }
        }

        /** @todo fredt - check against max value of type */
        public Object getValueObject()
        {

            long value = currValue;

            currValue += increment;

            Object result;

            if (dataType == Types.INTEGER)
            {
                result = ((int)value);
            }
            else
            {
                result = (value);
            }

            return result;
        }

        /**
         * reset to start value
         */
        public void reset()
        {

            // no change if called before getValue() or called twice
            lastValue = currValue = startValue;
        }

        /**
         * get next value without incrementing
         */
        public long peek()
        {
            return currValue;
        }

        /**
         * true if one or more values were retreived since the last resetWasUsed
         */
       public bool wasUsed()
        {
            return lastValue != currValue;
        }

        /**
         * reset the wasUsed flag
         */
       public void resetWasUsed()
        {
            lastValue = currValue;
        }

        /**
         * reset to new initial value
         */
        public void reset(long value)
        {
            startValue = currValue = lastValue = value;
        }

        public void reset(long value, long increment)
        {

            reset(value);

            this.increment = increment;
        }

        public int getType()
        {
            return dataType;
        }

        public HsqlNameManager.HsqlName getName()
        {
            return name;
        }

        public string getSchemaName()
        {
            return name.schema.name;
        }

        public long getIncrement()
        {
            return increment;
        }
    }
}
